• Journal of Drive and Control
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• v.12 no.3
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• pp.18-24
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• 2015

The plug-in hybrid electric vehicle has a high fuel economy and can be driven long distances. Its different modes include the electric vehicle, hybrid electric vehicle, and only engine operating mode. A power management strategy is important to determine which mode should be selected. The strategy makes the vehicle more efficient using appropriate power sources for driving. However, the strategy usually needs a driving speed profile which is future driving cycle. If the profile is known, the strategy easily determines which mode is driven efficiently. However, it is difficult to estimate the speed profile for a real system. To address this problem, this paper proposes a new power distribution strategy using a neural network. The average speed and driving range are used as input parameters to train the neural network system. The strategy determines a limit for the use of the battery and the desired power is distributed between the engine and the motor simultaneously. Its fuel economy can increase by improving the basic strategy.

• Journal of Advanced Navigation Technology
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• v.26 no.1
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• pp.35-45
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• 2022

In this paper, we modeled the devices used easily in PV system circuits. In addition, for full operation of the photovoltaic system, a complete operation system for the DC-DC buck-boost converter and the MPPT control system was modeled and simulated to confirm good operation. we were constructed an actual system with the same conditions in the simulation and experimented. The purpose is to confirm the stable power supply through the load leveling by presenting the PCS considering ESS of photovoltaic power generation. we will do study to apply hybrid capacitors that have high energy density to the same size compared to the EDLC to DVR. As a result, we proposed a single-phase 3 kW grid-connected solar power converter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.597-598
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• 2005

Recently, the performance of portable electric equipment can often improved by a Li-ion battery assisted by a supercapacitor. A supercapacitor can provide high power density as well as a low resistance in the hybrid system. In this study, we have prepared, as the pluse power souce, a commercially supplied Li-ion battery with a capacity of 700mAh and AC resistivity of $60m\Omega$ at 1kHz and nonaqeous asymmetric hybrid capacitor composed of an activated carbon cathode and MCMB anode, and have examined the electrochemical characteristics of hybrid capacitor and the pulse performances of parallel connected battery/hybrid capacitor source. The nonaqueous asymmetric hybrid capacitor, the stacks of 10 pairs of the cathode, the porous separator and the anode electrode were housed in Al-laminated film cell. The hybrid capacitor, which was charged and discharged at a constant current at $0.25mA/cm^2$ between 3 and 4.3V, has exhibited the capacitance of 100F. And the equivalent series resistance was $32m\Omega$ at 1kHz. By combining a Li-ion battery and a hybrid capacitor, the pulse performance of battery can be improved 23% in run time under a pulse discharge of 7C-rate.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.357-362
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• 2017

Among the lithium metal oxides for asymmetric hybrid supercapacitor, $Li_4Ti_5O_{12}(LTO)$ is an emerging electrode material as zero-stain material in volume change during the with the charging and discharging processes. The pulverized LTO powder was observed to show the enhanced capacity from 120 mAh/g to 156 mAh/g at C-rate (10, 100 C). Hybrid supercapacitor module(48V, 416F) was fabricated using an asymmetric hybrid capacitor with a capacitance of 7500F. As a result of the measurement of C-rate characteristics, the module shows that the discharge time is drastically reduced at more than 50C, and the ESR and voltage drop characteristics are increased. The energy density and power density were reduced under high C-rate conditions. When designing asymmetric hybrid supercapacitor module, the C-rate and ESR should be considered As a result of measuring the 5 kw UPS, it was discharged at the current of 116A~170A during the discharge in the voltage range of 48V~30V, and the compensation time at discharge was measured to be about 33.2s. Experimental results show that it can be applied to applications related to stabilization of power quality by applying hybrid supercapacitor module.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.708-720
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• 2020

Core-wide temperature distribution in sodium-cooled fast reactor plays a key role in its decay heat removal process, however the prediction for temperature distribution is quite complex due to the conjugate heat transfer between the assembly flow and the inter-wrapper flow. Hybrid medium model has been proposed for conjugate heat transfer modeling in the core. The core is modeled with a Realistic modeled inter-wrapper flow and hybrid medium modeled assembly flow. To validate present model, simulations for a three-assembly model were performed with Realistic modeling, traditional porous medium model and hybrid medium model, respectively. The influences of Uniform/Non-Uniform power distribution among assemblies and the Peclet number within the assembly flow have been considered. Compared to traditional porous medium model, present model shows a better agreement with in Realistic modeling prediction of the temperature distribution and the radial heat transfer between the inter-wrapper flow and the assembly flow.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.739-743
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• 2000

With significant development of power electronics technology the proliferation of nonlinear loads such as such as static power converters has deteriorated power quality in power transmission distribution systems. Notably voltage harmonics resulting from current harmonies produced by the nonlinear loads have become a serious problem in many systems Moreover momentary interruptions and voltage sags are responsible for many of the power quality problems found in typical industrial plants. Int his paper proposed 3 phase hybrid series active power filter is not only for harmonic compensation but also for harmonic isolation between supply and load and for voltage regulation and imbalance compensation Through computer simulations we have verified the effectiveness of the proposed system.

• Journal of Power Electronics
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• v.13 no.4
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• pp.719-728
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• 2013

A novel hybrid active power filter (NHAPF) that can be adopted in high-voltage systems is proposed in this paper. The topological structure and filtering principle of the compensating system is provided and analyzed, respectively. Different controlling strategies are also presented to select the suitable strategy for the compensation system. Based on the selected strategy, the harmonic suppression function is used to analyze the influence of system parameters on the compensating system with MATLAB. Moreover, parameters in the injection branch are designed and analyzed. The performance of the proposed NHAPF in harmonic suppression and reactive power compensation is simulated with PSim. Thereafter, the overall control method is proposed. Simulation analysis and real experiments show that the proposed NHAPF exhibits good harmonic suppression and reactive power compensation. The proposed compensated system is based on the three-phase four-switch inverter, which is inexpensive, and the control method is verified for validity and effectiveness.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.84-86
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• 2018

Active hybrid solid state transformer(AHSST) is newly emerging as a device to maintan the power quality of power distribution. AHSST has a simple structure in which a power electronics device is connected in series to a conventional distribution transformer. The connected power electronics device maintains the constant voltage regardless of the primary grid voltage fluctuation through the secondary voltage control to improve the power quality. It also has a simple structure compare to conventional solid state transformer system and can achieve the same performance with fractionally-rated converter. This paper proposes an multi-level converter based on AHSST system that has a simpler control method and wider voltage control range than the conventional AHSST. The proposed system is verified by simulations.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.1
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• pp.7-12
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• 2007

It is strongly requested to reduce fuel consumption because of high oil price and exhaust gases of road vehicles for environmental preservation. To solve these problems, several types of hybrid vehicles have been developed. Among them, flywheel hybrid vehicle using variable displacement pump/motor was already proposed as one of the feasible hybrid systems in place of hybrid vehicle by the conventional storage battery. The proposed flywheel hybrid vehicle is to keep constant pressure of high pressure line by the control of swash plate angle of flywheel pump/motor as pressure compensator. The efficiency of the overall system depends severely on the efficiency of hydraulic pump/motor in the energy saving hydraulic control system by simulation. According to the control methods of swash plate angle of piston pump/motor, there remain several problems to be solved. In this paper, experimental setup for energy saving is fabricated and the efficiency of energy saving is investigated by experiments with respect to various experimental conditions.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.778-783
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• 2012

Due to the increase of oil price, the needs of the reduction of the fuel cost is rising. Therefore, necessity of hybrid vehicle that runs with engine and the electric motor is on the rise. In order to improve the performance of hybrid vehicle, many researches is carried out. Hybrid vehicles have been developed with the various layout such as serial type, parallel type, power split type, and multi-mode type. The multi-mode hybrid vehicles are designed to show the efficient driving characteristics at low speed and high speed. But the multi-mode system have the problem such as frequent clutch engagement. Frequent clutch engagement causes the shock of vehicles, and the shock inhibits the ride comfort. In this study, automation mechanism of clutch operation is proposed to mitigate the shock at engaging clutch. For this purpose, the dynamic characteristics of motor control is numerically analyzed by using Matlab/Simulink.